[cityjohn]

Hopefully cleaning the terminals and checking for voltage will fix them. If not, as you mentioned, check the body-to-lid wiring. Lots of info on this; search for elephant. Most of these:

• no license lights
• no reverse lights
• trunk won't open
• trunk won't stay closed
• "trunk is ajar" indicator
• convertible top won't operate/car thinks trunk is open

...can be traced to broken wires in your elephant. It happens to all E46 cars, and the damage isn't always apparent as it can hide inside unbroken insulation.

As far as fuse numbers go, there's no one fuse for these license plate bulbs, just a general light circuit fuse (number 9 and number 32). If other lights work then this isn't the problem.